Lens coupled range finder for cameras



Feb. 5, 1952 c, c, s n- 2,584,818

LENS COUPLED RANGE FINDER FOR CAMERAS Filed Nov. 18, 1946 5 Sheets-Sheet l Feb. 5, 1952 c. c. SMITH ENS COUPLED RANGE FINDER FOR CAMERAS 5 Sheets-Sheet 2 Filed Nov. 18, 1946 Feb. 5, 1952 c. c. SMITH LENS COUPLED RANGE FINDER FOR CAMERAS 5 Sheets-Sheet 5 Filed Nov. 18, 1946 Feb. 5, 1952 c. c. SMITH 2,584,818

LENS COUPLED RANGE FINDER FOR CAMERAS Filed Nov. 18, 1946 5 Sheets-Sheet 4 Feb. 5, 1952 c, c, SMITH 2,584,818

LENS COUPLED RANGE FINDER FOR CAMERAS Filed Nov. 18, 1946 5 Sheets-Sheet 5 W 7 3 57 I 55 L 66 7/ *1 58 I 2%47'1/11/mfiffi17 I CLARENCE C. SMITH, f

Patented Feb. 5, 1952 1 8 UNITED STATES PATENT OFFICE LENS COUPLED RANGE FINDER FOR CAMERAS.

Glarence G. Smith, Flushing, N-. Y.', assignor of one-half. toEug'en'e F. Hartley, Onancock,:.Va.

ApplicationNovember 18, 19.46, Serial'No. 711L668 4-Claims. (CI. 95-44 I This invention relates to photographic cameras focus the tubes on the subject and thereby move and in particular. to viewfinding' and focusing the lens of the camera and bring it-into focus with operations; respect to the subject to be photographed.

Preparatory to making a photographic expo- In other words, the present invention provides sure, so far as I am aware, it isa commonprac- 5 for viewfinding and/or framing and alsol'ocustice to determine or guess at the distance of ing, without requiring the operator toshift his the object from the camera and then" focus the sight from one operation to the other, whereby camera accordingly. After focusing the camera, the operator is enabled to maintain the image the operator looks into the viewfinder and moves in the desired position in the viewfinder while the camera until" the object appears in the viewfocusing the camera. finder and then the camera is tilted in various In the drawings, directions until the object has been satisfactorily Figure 1 is a side view of an ordinaryform of framed in the viewfinder. The camera is then foldable hand camera, the front of the camera in condition for making an exposure, care being box' being in open position and the bellows of taken to maintain the object properly located in the camera extended, the top portion of the the viewfinder at the time of the exposure. If, adjacent side of the camera box being broken in the meantime the distance from the camera away to show some of the parts of the present to the object has changed, as when" the object is v t o moving, thus requiring a change in focus, the Figure 2 is a plan section on the line 2--2 of operator must shift his sight from the view-- Figure 1;

finder to the focusing mechanism for changing Figure 3 is a detail cross sectional view on the the focus to meet the new conditions. While line 3'3 of Figure 2;

thus refocusing. the camera, the latter may have Figure 4 is a detail sectional view on theline been inadvertently moved to such' an extent that 44of Figure 3;

the object will be located in an undesirable posi- Figure-5 is adetail fragmentary sectional View tion in the viewfinder or it may not-even appear on the line 5 -5'of Figure 3;

in the viewfinder. It will thenbecome necessary Figure 6' is a front elevation showing the to again frame the object in the viewfinder. If mounting of the lens mechanism on'the door of the distance has again changed, then focusing'and the camera;

viewfinding will'have to'be-repeated until asatis- Figure 7' isa plan view of Figure 6;

factory condition of focus and View framing has Figure S-is a verticle longitudinal sectional view been accomplished. Thus the desired poistionof Figure 6; and ing of the image in the viewfinder and the'sub Figure 9' is a p an sectional view on the line sequent focusing of the camera as commonly 99ofFigure 6. accomplished is a difficult, annoying and objeo- Figure 10 is a detail fragmentary sectional view tionable task: illustrating the rear stop for the lens carriage.

The principal object of the present invention For-anunderstanding ofthe present invention, is to avoid the above mentioned'objections and there-has been shown, more particularlyin Figto provide for accurately and satisfactorily foure'lof the drawings, the camera box or casing! cusing the camera while continuing to look into 0 of' any ordinary or preferred formof folding hand the finder so as to maintain the image properly camera. The reference character 2' designates in the viewfinder. This is particularly important the usual front of the camera box hinged or in photographing a moving subject as the campivoted at its'bottom edge as at 3, and shown in era boxmay be moved to follow the moving-suba horizontal open position in Figures 1 and 2 of ject and thereby maintain the image in its dethe drawings: There is also the usual or presired position in the viewfinder while the focusferred formof bellows i having suitable lens ing operation is being performed. In carrying mechanism 5- at the front of thebellows. The out' this feature of the invention, provision is lens-mechanismand the front of the bellows are made for utilizing sighting tubes for viewfinding, supported on thetop side of the foldable front 2' view framing and focusing purposes; Furtherof the camera box in the open position thereof more, provision is made for enabling the operator and mounted to slide back and forth so thatthe to look through a pair of sighting tubesfor viewbellows may be extended for exposure purposes finding and framing purposes, andto adjust the and may also be collapsed into the camera box sighting tubes, while continuing to viewthe subto permit of the upward folding of the front 2 ject through said tubes, in'such a manner-as to into its closed position. These parts are com- 3 mon and well known and form no part of the present invention.

In carrying out the present invention, two sighting tubes E and 'l' are employed for viewfinding and framing and also for focusing purposes. These tubes are duplicates in construction and mounting and, in the present embodiment of the invention, are shown as disposed in the same horizontal plane above the bellows 4 and within the top portion of the camera box which has been extended upwardly so as to house and accommodate these sighting tubes. r'he back wall of the camera, as shown in Figure 2, may be provided with openings 8 and S in alignment with the rear ends of the respective tubes so that the operator may conveniently look through the tubes from the back of the camera. Another arrangement has been shown in Figure 1, wherein a section A of the camera box back may be hinged at its top edge, as at a, so that it may be swung upwardly to expose the rear end of the tubes 6 and l for viewing purposes. When in its upright open position, the part A functions a a shield to shield the eyes against light when looking through the viewing or sighting tubes. In order that the sighting tubes may be adjusted to the spacing of the eyes of any particular operator, provision is made for slidably moving the tubes towards and away from one another, and thi feature of the invention will now be described.

Each sighting tube is mounted upon a carriage it: in the form of a, rectangular box or casing open at its front and rear ends and enclosing the sighting tube. Beneath the carriage is a horizontal shelf or partition if on which the carriages are mounted to slide transversely of the camera towards and away from one another. The back wall 12 of each carriage terminates short of the back wall of the camera box and is provided with a slot or opening 13 through which the rear end of the sighting tube projects. Horizontal flanges i4 and 15 project rearwardly at the top and bottom edges of the slot is and lie respectively above and below the tube, the latter being pivoted to swing horizontally upon a vertical axis afforded by suitable pivot connections 16 between the tube and the respective flanges. The forward end portion of the sighting tube is supported in a manner as will be hereinafter described.

For the purpose of adjustably moving the carriages 10, there is provided a horizontal shaft 11 extending through the s de walls of the carriages and journaled as at i8 and 19 upon opposite upright side walls of the camera box. Each carriage is provided with nuts 20 and 2! fixed to the upright side walls of the carriage and receiving the shaft l1. This shaft is provided with screw threaded portions 22 for the nuts of one carriage and 23 for the nuts of the other carriage. The screw threads 23 are reversely arranged with respect to the screw thread 22 so that by turning the shaft H, the carriages will be moved simultaneously in opposite directions for the purpose of adjusting the spaced relation of the carriages and likewise the sighting tubes. A suitable knob, finger piece or handle 24 is provided upon one end of the shaft IT and at the outer side of the camera box for convenience in rotating the shaft l1, whereby an operator may turn the knob 24 and thereby shift the carriages and bring the tubes into registered alignment with the eyes of the operator. When the tubes have thus been set in accordance with the spacing of the eyes of the operator, a subsequent change in the spacing become necessary only when the camera is being used by another operator having an eye spac different from that for which the sighting tubes were originally set. When the sighting tubes have been set in accordance with the spacing of the eyes of the operator, the latter may then look through the tubes with both eyes and the camera may be hand manipulated in the usual manner to bring the object to be photographed into view in the tubes. The camera box then should be hand manipulated to dispose or frame the image of the object correctly within the viewfinder afforded by the sighting tubes 6 and 1.

Finding of the proper focus for the lens mechanism is accomplished, in a manner hereinafter described; and is based on the well known method of range finding by triangulation. Here, the distance between the tubes, as set to the spacing of the eyes of the operator, is employed as the base of the triangle, while the tube sighting lines extending from the ends of such base to and intersecting on the object viewed through the tubes constitutes the other sides of the triangle. After adjustably spacing the sight tubes to the spacing of the operator' eyes, the tubes are swung or moved on their pivot points 16 so as to toe inwardly the front ends of the tubes until the longitudinal sight lines of the tubes intersect on the object to be photographed. An embodiment of means for accomplishing this result includes a horizontal shaft 25 disposed in front of the shaft l1 and journaled at its ends as at 25 and 21 on the inner faces of the opposite upright side walls of the camera box. This shaft extends loosely through the upright side walls of the carriages 20 so that the latter are permitted to slide back and forth on the shaft. This shaft also functions to prevent vertical swinging of the carriages on the shaft l1. Beneath each sighting tube there is provided on the shaft 25 a cylindrical member 28 which is mounted to slide longitudinally on the shaft but held thereto against rotation on the shaft preferably by having the shaft 25 noncircular in cross section, preferably square. The cylindrical part 28 is provided with an axial opening of the shape of the cross section of the shaft to receive the shaft, whereby the cylindrical part may rotate with the shaft and slide longitudinally thereon. The cylindrical member 28 is held to the carriage ID in any suitable manner so that they will move together. The forward end portion of the sighting tube rests upon the top of the cylindrical part 28 and the latter is provided with a cam groove 29 in which travels a pin or projection 30 depending from the tube, so that when the shaft 25 is turned, the cylindrical part 28 will be likewise turned and the walls of the cam groove 29 wiping across the pin 30 will cause the sighting tube to be swung or turned upon its pivot pin IS. AS best shown in Figure 2 of the drawings, it will be seen that the cam grooves 29 are reversely disposed whereby the tubes will be swung simultaneously and equally in opposite directions when the shaft 25 is turned.

Suitable provision is made for rotating the shaft 25, and one embodiment of such means has been shown in the drawings as including a crank arm 3|, mounted upon the shaft 25 between one of the carriages l0 and the adjacent upright side wall of the camera box. This crank arm is mounted to slide on the shaft longitudinally thereof but is held thereto so as to rotate therewith. The crank arm 3| depends from the shaft 25, extends downwardly through an opening b in the horizontal partition II, and rests against the periphery of a cam 32 disposed below the camera box. 'The cam the slide 31,

"tionof the-tubes "on a-"threaded portionof the shaft l1,-and this *nut is provided in *one edge with an upright shaft and having its longitudinalaxis parallel therewith. This cam 'is mounted to rotate on a horizontal axis and is rotatably supported at lts outer end on a bearing 33 carried "by the inner face'of the adjacent upright side wall of the 3.2 .is "tapered inwardly from the adjacent side of'the camera box. For rotating the cam 32, 'the'latter is provided at its outer end with a grooved'pulleymember '34 over which is trained a cord '35 having its upper-end suitably secured to the pulley. Thiscord depends from the pulley and extends downwardly to an other grooved pulley 36 rotatably supported within the camera box I adjacent and just above the level of the hinge connection3 for thefront of the camera box. The lower portion of the cord extends forwardly in a horizontal direction and is connected to the rear end a of a "slide 31 disposed horizontally above the front member 2 and provided at opposite ends with depending leg portions 38 mounted to slide upon the frontmember 2 towards and away fromthe camera box. Any suitable cord tightening means, "such as eturn buckle, not shown, maybe provided for taking up slack in the'cord 35.

"for'a cord tightener would be at'the rearend of where a -turn buckle connection between cord '35 and the slide 31 would serve not only toconnect 'theparts *but' would also provide adjustable means fortaking up-slack-in the cord.

The under face of the slide *31 is toothedor pro vided with a rac'k 3-8 meshing with the'top side of 'a gear or pinion carried by a horizontal shaft 4| mountedforrota-tion upon the front member-2 andhavingoneend projectedbeyond the adjacent longitudinal -edge ofthe front member 2 and provided with ak-nob or finger piece 42 for use in rotating the shaft. Itwillnow be understood that the shaft 4! may be rotated so as tomove the slide 31 outwardly fromthe camera box and thereby pull downwardly-upon the cord '35 and thus rotate the cam I32 which in turnwill swing the crank arm 3| and thereby rotate-the *shaft '25 and cause swinging movements of the sighting tubes 6 and 1 before described. p In anyrange findingoperation the amount of in the manner hereinswing or pivotal movement of the sighting tubes '6 and! depends upon-the spaced relation of the tubes. In other 'words, -the closer together the tubes, the less swinging movement will be re- *quired to intersect the sight lines -ofthe tube on the object. To providefo'r theproper swinging movement of the tubesthe crank arm-3| .must

occupy a predetermined position on the cam-with respect-tothe length-thereof and in accordance with thespaced relation of the sightingtubes.

When the crank arm ls -a't the larger end. of the cam the latter will impart the-maximum movement to the crank arm. The swinging movement of'the crank arm-will decrease progressively as theposition of the arm'is shiftedtowards the smallerend of the cam. "Toautomaticallyset the crank arm-3-l to its proper position longitudinally of the cam 32 in accordance with the spacedrela- 6 and 1- a nut 43 is provided 'groove' constituting a seat receivinga :periph eral portion of the enlarged and-preferably'cir- -cular or segmental head "The head prevents rotation of-the nut on the :shaft 1 1, that whenthe-shaf-t is rotated,

A convenient 'locat'ion the nut is fed along the shaft and moves the crank arm 31 along the shaft .25 until it comes to rest at the proper position along the .cam"32 when the rotation of the shaft 11 has been stopped'with the sighting tubes 5 and 1 in their proper spaced relation. Accordingly, it will be understood that the act of adjustably spacing'the sighting tubes automatically moves the crank arm 3| along the shaft 25 to its proper cooperative position longitudinally of the cam 30 for subsequently :pivotally swinging the sighting tubes, when the shaft 25 is turned'by the action of the cam against the crank armun'der the control of the finger piece 42 to intersect the tube sight lines on the object to be photographed.

The shaft 4! employed for adjustably swinging the sighting tubes 6 and 1 to intersect the sight lines on the subject to be photographed, is also employed for moving the lens mechanism 5 for focusing the camera, and for this purpose is extended beneath the bellows 4 and provided with a pinion 46 in mesh with a toothed rack 41 associated with the lens mechanism 5 sothat upon manipulation of the finger piece '42 to turn the shaft 4! and thereby swing or turn the'sightl'ng tubes, as hereinbefore described, the pinion "46 will simultaneously operate to proportionately move the lens mechanism 5 and set it at the proper distance from-the position of therphotographically sensitive member in the camera box. Thus, it will be understood that the sighting tubes are used as a view finder and that the hand manipulation of the'piece '42 in setting the movablecamera lens mechanism for focusing purposes while the operator continues to look through the sighting tubes. This obviates the necessity ofshift ing the sight of the operator from the object to be photographed-in order to focus the camera.

The sighting tubes are'provided with any'suitable or preferred lens system such as aconcave lens 48 at the front and a convex lens at the rear of the tube so as to provide a stereoscopic effect object to be photographed.

To assist the operator in accurately adjusting the sight tubes for focusing purposes and to-eliminate the personal equation or judgment of the operator, each tube is provided at its front with a flared or enlarged portion 50 togetherwitha transparent plate 5! at the front open end of the flared portion 50. Each transparent plate 5! is provided with suitable markings or indices. When these markings appear as though brought together, merged or registered, the sight'lines ofthe tubes are then intersectedon thecbiect to .be photographed, and thiscondition indicates that the camera is in focus. .Any suitable. or preferred form of markings on plates5i maybe employed. For instance, as shownin Figure 3, one of the markings 53 may be a circle, and the other,.no.t shown, may be a dot. In using these markings, the sighting tubes are swungon their pivots until the dot appears at the center of thecircleand these markings also appear as'being on the object, in which condition the registered marks indicate that the camera lens mechanism hasbeen properly set for the distanceto thesubjecttobe photographed and the camera is infocus.

The flared portions-iuoftthe.sighting tubesare frame provided by the walls desired view has been brought into vision through.

the sighting tubes, the view has been found, and then by proper manipulation of the camera box, the view may be selectively disposed within the of the flared portions of the tubes which, of course, produce the a single frame due to the stereoscopic effect of the sighting tubes. While the flared portions may be of any form in cross section, a rectangular cross section is preferred for the reason that a view can most conveniently and accurately be disposed in the desired position within a rectangular frame as the straight sides of the frame afford the most convenient shape with which to align, dispose or center the view and thus frame it.

As shown in Figure l of the drawing, ing tubes are located above the bellows and the lens mechanism. Obviously, they could be located below the bellows and lens mechanism and function properly in this position. However, there is a necessary relation of the sighting tubes with respect to the camera lens, and this relation is that of being disposed equally on opposite sides of a plane located between the tubes, disposed at right angles to the plane of the tubes, and passing through the axes of the lens, so that the sight lines of the tubes may intersect in such plane. The bellows, the photographically sensitized member, and perhaps other parts of the camera, prevent the locating of the sighting tubes between the top and bottom of the camera box and in the same horizontal plane with the axis of the lens. For convenience of expression in the claims, the relation of the tubes and the lens will be expressed as that of the tubes being disposed equally at opposite sides of the axis of the camera lens. Inasmuch as the carriages l3, upon which the tubes are mounted, are always moved equally in opposite directions when setting or spacing the tubes to the distance between the eyes of the operator or user of the camera, this important relation of the tubes and lens is preserved. Also the turning or tilting of the tubes upon their pivotal mountings is to the same degree or angle for one tube as for the other, and thus the relative positions of tubes and lens axis is always preserved.

For moving the lens mechanism for focusing the camera, I utilize the shaft 4| also employed for adjustably swinging the sighting tubes 6 and 1. Reference is made to Figs. 6-9, inclusive, for an understanding of this feature of the present invention. The shaft 4! is extended beneath the bellows 4 and provided with a pinion 46 meshed with the under side of a toothed rack 41 provided on the under side of a carriage 53 in the nature of a fiat plate, the longitudinal edge portions of which are slidably supported on guide ways 54 carried by the door 2 and provided on their inner faces with longitudinal grooves 55 slidably receiving the longitudinal edges of the carriage 53. It will thus be seen that the members 54 constitute a track having slideways 55 receiving the edges of the carriage 53. The lens mechanism 5 of the camera is provided with a base or crossbar 55 suspended from the lens mechanism by downwardly converged hangers or brackets 51, and the base or crossbar 55 is slidably supported upon the carriage 53. The base member 56 is separate from the carriage and may be clamped to the carriage 53 so as to move therewith. Suitable mechanism for this purpose includes a pair of upright clamp members 58 pivoted at 59 to the respective brackets or hangers 51. In the drawings, these clamp members 58 are pivoted to the effect of the sight rack 41, the carria e 53 moved to that position rear sides of the hangers or brackets 51, but may be located in front thereof as may be desired. The lower end of each clamp member is curved inwardly to form a hook 60 to embrace and engage beneath a horizontal flange 8| or edge portion of the carriage 53. A helical spring 82 is interposed between and exerts pressure outwardly in opposite directions against the upper finger portions 83 of the clamp members so as to hold the clamp in frictional engagement with the opposite edges of the carriage 53 and thus clamp the lens mechanism to the carriage 53 for movement therewith. By manipulating the shaft 4!, the pinion 46 may be turned so as to move the rack 41 and the carriage 53 and the lens mechanism clamped thereto in either direction for focusing purposes.

To lock the carriage 53 in any adjusted position along the track 54, a locking bracket 64 is provided on the inner face of the door 2 and has a laterally projecting flange provided on its under side with a tooth or teeth with which the teeth of the pinion 45 may be engaged by thrusting the shaft 41 longitudinally inward, the shaft being mounted to permit such manipulation thereof. When the pinion 46 is thus engaged with the ribs or projections of the bracket 64, it is locked against being turned and at the same time being engaged with the teeth or ribs of the will be locked against accidental movement and therefore the lens mechanism may be held in any adjusted position. By pulling the shaft 4| outwardly, the pinion 46 may be disengaged from the bracket 54, and thus freed for turning and then by turning the shaft Al the carriage and the lens mechanism, clamped thereto by the clamp members 58, may be moved towards or away from the camera box.

By pressing inwardly in opposite directions on the handles or finger pieces 53 of the clamp members 58, the latter may be disengaged from the carriage 53 so as to permit of the lens mechanism being moved by hand along the carriage 53 and pushed back into the camera box. During this operation the shaft 4| should be at its inner limit in engagement with the rack 41 and the bracket 64 so as to be in locked position to prevent movement of the carriage 53. There is provided within the camera box a keeper 56, in the form of a flat plate disposed in alignment with the carriage 53 in the open position of the door or front 2, so that the clamp jaws 60 may be slidably moved from the carriage to opposite edges of the keeper in the rearmost position of the carriage, each jaw being of a length to bridge the space between the adjacent ends of the carriage and keeper when being moved in either direction across the space between the carriage and keeper. It is not necessary to entirely disengage the jaws of the clamps from the edges of the carriage 53 to permit sliding of the base member 55 thereon and thus the jaws 60 will effectively guide the base member in moving to and from the parts 53 and 66.

With the bellows and lens mechanism within the camera box and the front or door 2 closed, the clamping jaws 6|! are engaged with opposite sides of the keeper 66 so as to hold the bellows collapsed and also prevent shaking of the lens mechanism. It will be, of course, understood, in the closed condition of the camera, the carriage 53 will be at its rear or inner limit having been by manipulation of the knob 42 and stopped in this position by having its rear end engaged with the closed rear end 61 handle, fingerpiece (see Figure 10) of each groove or slideway 55. When the carriage 53 is stopped at its rear limit, the shaft 4|, is pushed inwardly so as to enga not only the rack 41 but the tooth or teeth on the lock bracket 64 so as to hold the carriage in its initialrearmost position.

In the closed condition of the camera, the outer end portion of the shaft 4] may be received in a notch 42' shown in Fig. 1, or, asshown in Fig. 9, the knob 42 may be received in. a notch 42' in the adjacent edge of the door, thereby to permit of the door being closed without interference by the shaft 4i and the knob 42.

To put the camera in condition for use, the front or door 2- is opened until the carriage53 is in alignment with the keeper 66. Then thehandies or finger pieces 63 of the clamp are pressed inwardly to release the grip of the clamping jaws 60 upon the edges of the keeper 66, whereupon, by pulling forwardly on the fingerpieces 63, the lens mechanism and the bellows may be pulled out of the camera box, the jaws, slidingreadily from the keeper to the carriage and then along the carriage until automatically brought to a stop by reason; of the base bar '56' coming into contact with a stop, shoulder 61 rising from the front of the carriage, 53; It will be understood that during. such operation, the carriage is held fi ed: y the pinion 46 engagin oth the k 41 on the carriage and the holding bracket 64.

Whenthe lens mechanism has been pulled out to its limit on the carriage 53, i. e. as far as the stop 61 thereon will permit, the camera will be set for infinity focus, i. e. focused on objects 100 feet or more in front of the camera. This 11;

initial position of the lens mechanism is the starting point forfocusing on nearer objects, for which the lens must be moved further away from the sensitized plate or film, by pulling the shaft 41 outwardly to disengage the pinion" 46 from the keeper 64, and then manipulating the knob 42v to turn the shaft and pinion so as to move the carriage 53, and the lens mechanism secured thereto by the clamps 58, forwardly while at the same time looking through the sighting tubes, which are being swung inwardly by the manipulation of the shaft 4| and the connections therefrom tothe tubes. It will thus be understood that by the: manipulation of a single member, 1. e. the

or knob 42, the camera is focused, while the operator is looking through the sighting tubes and without requiring the operator' to shift his eyes from the sighting tubes.

As indicated in Figs. 7 and 9 the door 2 has one member 68, of latching means for holding,

the door closed, such member being located on the inner face of the door and at the outer end thereof. It will be remembered that the carriage 53 is moved to its rear limit preparatory to closing the door, and in this position the front end edge of the carriage lies in rear of such latching member in the closed condition of the camera so as not to interfere with the function of the latching member in locking the door.

The sighting tubes and associated mechanism are set at the factory with respect to the position of the lens mechanism when the latter is at infinity focus. Thereafter the lens mechanism will be moved for focusing purposes by and in accordance with the adjustment or manipulation of the sighting tubes to intersect their sight lines on the subject to be photographed. The procedure for setting the mechanism is as follows:

The camera door 2 is opened to its limit as shown in Figures 1, 2, 8 and 9. Then, by manipulation of the finger portion 63 of the clamping means, the lens mechanism is released from the keeper 66 in the camera box and then pulled out upon and along the carriage 53 until arrested by the stop 57 on the carriage. This is the position of the lens mechanism when. at infinity focus or in other words, set for photographing an object substantially 100 feet in front of the camera. This is in accordance with standard practice and requires no further explanation, except to state that when the door 2 is closed, the carriage 53 is at its rear limit and is locked in that position by the engagement of the pinion 46 with the keeper E5 and the rack 47 on the bottom of the carriage, which assures that the stop 67' will be in the position to halt the forward or outward movement of the lens mechanism at infinity focus when the lens mechanism is being drawn forwardly on the carriage. Withthe lens mechanism at infinity focus, the person who is adlusting the camera will first look through the sighting tubes 8 and l and adjust the spacing thereof to the spacing of his eyes by manipulation of the finger piece 24, which moves the crank arm 3! to its proper position longitudinally of the cam 32. Continuing to look through the sighting tubes and at an object at or slightly more than 100 feet away from the camera, the tubes 5 and! are swung on their pivots i t until the sight lines of the tubes intersect on the said object as indicated by the markings on the transparent plates 5| of the tubes which are now in registration or in some predetermined relation and appearing as upon the object to be photographed. This is the proper position of the sighting tubes when the lens mechanism is set at infinity focus, because the sight lines of the tubes now form an isosceles triangle having as its base the imaginary line between the eyes of the adjuster, the altitude of such triangle being the distance to the object to be photographed. The tubes 6 and "i may be swung on their pivots by pulling downwardly on the cord 35, thereby rotating the cam 32'which in turn swings the crank arm 3 i, therebyrotating the shaft 25 on which are the parts 28 having the cam grooves 253' in which work the pins 33; carried by the sighting tubes and by which the sighting tubes are swung on their pivots l8. During this adjustment of the sighting tubes, the lens mechanism is held fixed at infinity focus because the pinion 45 engages the rack 4! and the keeper 65, and therefore the sighting tubes are set properly in accordance with the position of the lens mechanism to photograph the object onwhich the sight lines intersect at about I06 feet in front of the lens. The cord 35 should be provided with some kind of cord tightening means, as for instance, a turn-buckle connection or other adjustable connection, say between the cord and the rear end of the rack 31', such cord tightener being employed to tighten the cord after the sighting tubes have been adjusted as above described.

What is claimed is:

1. In a photographic camera, the combination of settable lens mechanism, view-finding focusing means including a pair of sighting tubes, a carriage for each sighting tube, each sighting tube being pivotally mounted on its carriage, a rotatable carriage-shaft mounted upon the camera, nuts carried by the carriages and receiving the shaft, the shaft being provided with screw-threaded portions engaging the nuts, one screw-threaded portion being reverse to that of the other screw-threaded portion for moving the carriages towards and away from one another for adjustably spacing the tubes, a rotatable sighting tube shaft extending through the carriages. a cylinder for each carriage and mounted to rotate with and slide upon the sighting-tube shaft, each cylinder having a cam groove, each sighting tube having a pin in the cam groove of the adjacent cylinder for swinging the tube on its pivot, a crank arm rotatable with and slidable upon the sighting-tube shaft for rotating the said shaft, a rotatable cam associated with the crank arm for swinging the same, means on the carriage shaft for adjustably moving the crank arm along the cam to correlate the swinging of the arm to the spacing of the tubes, a pulley for the cam, a cord connected to and trained around the pulley, a shaft having a gear, a rack connected with the lens mechanism and associated with the gear, and a slidable rack associated with a gear on the last mentioned shaft, the cord being connected to said slidable rack.

2. In a camera, the combination with lens mechanism adjustable for focusing purposes, a pair of sight tubes pivotally mounted on the camera for range finding purposes, means for selectively spacing the pivotal mountings of the tubes, means for pivotally adjusting the tubes on their mountings to intersect their sight lines, means to co-relate such pivotal adjusting means to the spacing of the tubes, and means actuated by the tube adjusting means for simultaneously moving the lens mechanism for focusing purposes u'hiie looking through the tubes.

3. A camera having lens mechanism movable for focusing purposes, a pair of pivotally mounted sight tubes, means for adjustably spacing the tubes including a rotatable spacing shaft, means for adjustably turning the tubes on their pivotal mountings to intersect their sight lines including a rotatable tube adjusting shaft, the two shafts being parallel, the means for turning the tube adjusting shaft including a conical cam rotatable on its longitudinal axis disposed parallel with the tube adjusting shaft, a crank arm carried by the tube adjusting shaft for rotating the same and slidable thereon and lying against the periphery of the cam whereby rotation of the cam will swing the crank arm and rotate the tube adjusting shaft, means actuated by the tube spacing shaft for moving the crank arm along the cam in accordance with the spacing of the tube whereby to co-relate pivotal adjustment of the tubes to the spacing thereof, a handle connected with the cam for rotating the cam, and means connected to the handle and the lens for moving the lens to focusing position by the movement of the handle for pivotal adjustment of the tubes for range finding while looking through the tube.

4. A camera having lens mechanism movable for focusing purposes, a pair of carriages mounted upon the camera and movable towards and away from each other, a rotatable carriage spacing shaft mounted on the camera and connected with the carriages for adjustably moving them by rotation of the shaft, sight tubes located in the same plane and pivotally mounted upon the carriages for pivotal movement towards and away from one another, a rotatable tube adjusting shaft mounted on the camera in parallelism with the carriage spacing shaft and connected with the tubes for pivotally adjusting the same, a. traveling nut mounted on the carriage adjusting shaft, a tapered cam rotatably mounted on its longitudinal axis parallel with the tube adjusting shaft, a crank arm slidable upon the tube adjusting shaft and rotatable therewith, said crank arm bearing upon said cam and connected to the nut and movable with the nut longitudinally of the cam, a handle, means extending between the handle and the cam for rotating the latter to swing the crank arm and rotate the tube adjusting shaft and thereby pivotally adjust the tubes, and other means extending between the handle and the lens for moving said lens for focusing the same by the movement of the handle in rotating the cam while looking through the tubes.

CLARENCE C. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

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